Semiconductor devices or chips (hereafter referred to as just “chips”) may consist of a semiconductor base where all of the front end of the line (FEOL) processing is typically done to form the semiconductor transistors, capacitors, etc. and a back end of the line (BEOL) wiring where multiple wiring layers are formed to connect the various transistors, capacitors, etc. in the semiconductor base. The BEOL wiring may also have input/output (I/O) pads for connecting the chip to a next level of packaging such as a printed circuit board or a ceramic substrate. The semiconductor base is made from a semiconductor material while the BEOL wiring is made from metallic materials for wiring and dielectric material for insulation. The BEOL wiring does not contain semiconductor materials.
Current semiconductor chips may have a through silicon via which partially or entirely extends through the semiconductor base and the BEOL wiring. Such a through silicon via may be used, for example, to connect two chips by stacking them one on top of the other.